From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1KpglE-00053h-5a
	for qemu-devel@nongnu.org; Tue, 14 Oct 2008 06:04:16 -0400
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1KpglC-000538-9m
	for qemu-devel@nongnu.org; Tue, 14 Oct 2008 06:04:15 -0400
Received: from [199.232.76.173] (port=34005 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1KpglA-000535-S8
	for qemu-devel@nongnu.org; Tue, 14 Oct 2008 06:04:13 -0400
Received: from mx2.suse.de ([195.135.220.15]:58414)
	by monty-python.gnu.org with esmtps
	(TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60)
	(envelope-from <kwolf@suse.de>) id 1KpglA-0000Sf-B7
	for qemu-devel@nongnu.org; Tue, 14 Oct 2008 06:04:12 -0400
Message-ID: <48F46ED2.6000508@suse.de>
Date: Tue, 14 Oct 2008 12:05:06 +0200
From: Kevin Wolf <kwolf@suse.de>
MIME-Version: 1.0
Subject: Re: [Qemu-devel] Re: [RFC] Disk integrity in QEMU
References: <48EE38B9.2050106@codemonkey.ws>	<20081013170610.GF21410@us.ibm.com>	<6A99DBA5-D422-447D-BF9D-019FB394E6C6@lvivier.info>
	<20081013194328.GJ21410@us.ibm.com>
In-Reply-To: <20081013194328.GJ21410@us.ibm.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Reply-To: qemu-devel@nongnu.org
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: qemu-devel@nongnu.org
Cc: Chris Wright <chrisw@redhat.com>, Mark McLoughlin <markmc@redhat.com>, kvm-devel <kvm-devel@lists.sourceforge.net>, Laurent Vivier <Laurent.Vivier@bull.net>, Ryan Harper <ryanh@us.ibm.com>, Laurent Vivier <laurent@lvivier.info>

Ryan Harper schrieb:
> * Laurent Vivier <laurent@lvivier.info> [2008-10-13 13:52]:
>> What file type do you use (qcow2, raw ?).
> 
> Raw.

I guess the image is preallocated? What about sparse files (or qcow2,
anything that grows), do have numbers on those? In the past, I
experienced O_DIRECT to be horribly slow on them.

Well, looking at your numbers, they _are_ quite bad, so maybe it
actually was sparse. Then the preallocated case would be interesting.

Kevin